Method of preparing nano-dispersed high-all-trans-carotenoid microcapsules

A method of preparing nano-dispersed high-all-trans-carotenoid microcapsules, which comprises of the steps of:

• 1) milling crystallized carotenoid with more than 98% of all-trans and dichloromethane until particle size thereof is in the range of 2-5 μm, resulting in 10-20% carotenoid suspension;
• 2) continuously supplying the carotenoid suspension to a dissolving tank, while supplying dichloromethane after being preheated to 45-50° C. by a heat exchanger to the dissolving tank, maintaining the pressure at 0.2-0.3 MPa and the temperature at 35-40° C. in the dissolving tank, and with materials retention time of 4-12 minutes, to dissolve the crystallized carotenoid completely, resulting in dichloromethane solution with 0.5-2.0% of carotenoids;
• 3) continuously supplying dichloromethane solution with 0.5-2.0% of carotenoids to a crystallization device having a high gravity rotating packed bed and a liquid distributor;
• and also adding ethanol or isopropanol, with the weight of 5-10 times of dichloromethane solution, into the crystallization device;
• then precipitating carotenoid to be nano-crystal and obtaining a clear carotenoid dispersion;
• 4) continuously desolventizing the clear carotenoid dispersion under a reduced pressure in a wiped-film evaporator and obtaining alcohol dispersion with 10-20% of nano-dispersed carotenoid;
• 5) mixing the alcohol dispersion with nano-dispersed carotenoid and aqueous solution of antioxidant and protective colloid, and beating in another high gravity rotating packed bed;
• then spray drying the mixture to obtain nano-dispersed high-all-trans-carotenoid microcapsules.